diff --git a/Code.ts b/Code.ts
index ec5c893..bf7ed5b 100644
--- a/Code.ts
+++ b/Code.ts
@@ -65,6 +65,12 @@ function spreadsheetRowToObject(
   }, {});
 }
 
+function trashFiles(files: GoogleAppsScript.Drive.FileIterator) {
+  while (files.hasNext()) {
+    files.next().setTrashed(true);
+  }
+}
+
 function generateForCurrentRow() {
   const spreadsheet = SpreadsheetApp.getActive();
   const cell = spreadsheet.getCurrentCell();
@@ -82,10 +88,14 @@ function generateForCurrentRow() {
     '1ROyJXk-QANTHM6Jiw0ne3EQiR1f2UsLr'
   );
 
-  const out_file = source_file.makeCopy(
-    row['Document Name'] + row['Version'],
-    out_folder
-  );
+  const out_name = row['Document Name'] + '_' + row['Version'];
+
+  // Delete old files with the same name
+  trashFiles(out_folder.getFilesByName(out_name));
+  trashFiles(out_folder.getFilesByName(out_name + '.pdf'));
+
+  // Duplicate source document and open
+  const out_file = source_file.makeCopy(out_name, out_folder);
   const out_doc = DocumentApp.openById(out_file.getId());
 
   // Copy header